In northern Warren and southern Mercer Counties the sandstone underlying
the Rock Island (No. 1) Coal is termed the “Stigmarian” sandstone
because of numerous siliceous casts found in the bed. Many of the
fossils have been collected from an old mine dump and from ravines along
the Edwards River northeast of Aledo.
A number of representatives of _Sphenophyllum_, _Neuropteris_, and
_Annularia_ have been collected from ironstone concretions occurring in
shale that overlies the Colchester (No. 2) Coal about three miles
southwest of Alexis. They were found in a gully about a third of a mile
southeast of Center School.
[Illustration: uncaptioned]
[Illustration: _Plate 3_]
_Pecopteris_ 1×
_Ptychocarpus_ ⅗×
_Pecopteris_ ⅗×
_Mariopteris_ ⅗×
_Asterotheca_ ⅗×
_Spiropteris_ ⅗×
_Pecopteris_ ⅗×
In the same general area but about three miles due south of Alexis,
fossil plants also may be found in the clay pits of the Hydraulic-Press
Brick Company and the Northwestern Clay Manufacturing Company.